Writing to this will cause the kernel to drop clean caches, dentries and inodes from memory, causing that memory to become free.
To free pagecache:
echo 1 > /proc/sys/vm/drop_caches
To free dentries and inodes:
echo 2 > /proc/sys/vm/drop_caches
To free pagecache, dentries and inodes:
echo 3 > /proc/sys/vm/drop_caches
As this is a non-destructive operation, and dirty objects are not free-able, the user should run "sync" first in order to make sure all cached objects are freed.
8 comments:
Hello, When i try to perform this tip i got this error message:
bash: /proc/sys/vm/drop_caches: Permission denied
Even when i run the command by sudo.
can you please provide me the actual command that you have used here?
"sudo echo 3 > /proc/sys/vm/drop_caches" or "echo 3 > /proc/sys/vm/drop_caches" don't work.
Which version of kernel you are running? type command "uname -a"
2.6.32-24-generic
http://www.linuxask.com/questions/permission-denied-when-doing-redirection-with-sudo
Ariel, in order to redirect output with sudo you have to make it a full on bash command. For instance:
sudo bash -c “echo 3 > /proc/sys/vm/drop_caches"
Thank a lot! i always love to learn something new.
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